Boltrope attachment of flexible hull portion to a rigid hull portion of an rib

ABSTRACT

A rigid inflatable boat (RIB) has a rigid hull portion and a flexible hull portion with a connection between them. The connection is provided by a boltrope, or the like, received in a grooved anchor. The flexible hull portion includes an enclosure, preferably of a conforming fabric, with a number of inflatable bladders enclosed by the fabric. The boltrope is preferably attached to the fabric of the enclosure by textile tape and stitching. The enclosure fabric is impregnated with a finishing material, such as a resin, while in the position it will be in when containing inflated bladders, and is cured in that configuration. A transom is pivotally mounted to the rigid hull portion, and braces hold the transom in an upright position during use. The sides of the transom are scalloped to receive and position the flexible hull portion, and a significant amount of the flexible hull portion extends aft of the transom. A centrally disposed boltrope and grooved lugs may provide a rub strake for the flexible hull portion, and a boltrope at the top of the flexible hull portion may mount accessory components such as cleats, oarlocks, and thwarts. The conforming fabric may be tubular knit fabric spirally wrapped with a second fabric, flat (e.g. warp) knit fabric, non-woven fabric, triaxially woven fabric, or the like.

This is a continuation of application Ser. No. 618,147, filed June 7,1984, which was abandoned upon the filing hereof.

BACKGROUND AND SUMMARY OF THE INVENTION

Rigid inflatable boats (commonly known as RIBs), are useful in rescueoperations, especially in heavy seas, and in a variety of otherenvironments where the good stability, buoyancy, and other properties ofthese boats are particularly advantageous. In U.S. Pat. No. 4,498,413 arigid inflated boat has been described which is relatively simple toconstruct, versatile, relatively inexpensive, and easy to transport. Inpreferred embodiments illustrated in said applications, the boats haverigid hull portions generally at and below the water level, and flexiblehull portions generally at and above the water level. The flexibleportion comprises a flexible material, preferably an abrasion resistantfabric, which circumferentially surrounds a plurality of inflatablebladders.

The present invention relates to improved constructions of the rigidinflatable boats illustrated in and described in said co-pendingapplications, and utilizing the basic concepts of a rigid hull portionand a flexible hull portion. According to the present invention, aneminently practical RIB construction is provided which facilitates themodular construction of a rigid inflatable boat, provides desiredstability and other functional characteristics while allowing the boatto be transported or stored in a minimum volume configuration, andutilizes materials that are eminently suited for use as the enclosurefor the bladders.

According to one aspect of the present invention, a rigid inflatableboat is provided which includes: a rigid hull portion disposed generallyat, and below, the water level of the hull; a flexible hull portion, theflexible hull portion including an enclosure or shroud of flexiblematerial completely circumferentially surrounding a plurality ofinflatable bladders, and the flexible hull portion being positionedgenerally at, and above, the water level of the hull; and connectingmeans for connecting the flexible hull portion to the rigid hullportion, the connecting means comprising bead means formed on theflexible hull portion, and grooved anchor means formed on the rigid hullportion, and for cooperating with the bead means of said flexible hullportion. The bead means preferably comprises a boltrope or the like, andthe grooved anchor means preferably has a C-shape in cross-section.

The enclosure for the bladders, of the flexible hull portion, preferablyis of a conforming fabric. The term "conforming fabric" as used in thepresent specification and claims relates to a fabric that has propertiessuch that it may be formed to the required complex contour withoutpuckering. The majority of conforming fabrics are knit, such as warpknit or circular knit fabrics. However triaxially woven fabric, fabricswoven with elastic therein, velvet, and braided fabric also areconforming fabrics. The enclosure fabric is preferably attached to theboltrope by textile tape and stitching.

It is particularly advantageous to provide memory for the conformingfabric of the enclosure so that it tends to return to its use position,wherein it completely circumferentially encloses inflated bladders. Thismay be accomplished by impregnating the fabric with a finishingmaterial, such as a resin, and curing it while it is held in its desireduse position.

According to another aspect of the present invention, a rigid inflatableboat includes a transom, the transom providing for proper positioning ofthe flexible hull portion. The sides of the transom may be scalloped toreceive the flexible hull portion, and the boltrope may be affixed tothe rigid hull portion in the area of the transom. Preferably, thetransom is pivotally mounted to the rigid hull portion for pivotalmovement about a horizontal axis extending along the dimension ofelongation of the transom, so that the transom may be folded down sothat the boat will assume a low volume configuration during storage ortransport. A brace attached to the rigid hull portion and the transomholds the transom in an upright position during use, and positioning ofthe flexible hull portion may be facilitated by loosely affixing theenclosure fabric to the brace.

It is the primary object of the present invention to provide apractical, versatile, RIB. This and other objects of the invention willbecome clear from an inspection of the detailed description of theinvention, and from the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross-sectional view showing an exemplaryinterconnection between a bladder enclosure fabric and a boltrope;

FIG. 2 is a side view, partly in cross-section and partly in elevation,of an anchor means associated with the rigid portion of the hull of aboat, and utilizable with the boltrope of FIG. 1;

FIG. 3 is a side view, partly in cross-section and partly in elevation,showing a portion of an exemplary RIB according to the invention,adjacent the transom;

FIG. 4 is a top plan view of the right half of an exemplary RIBaccording to the present invention;

FIG. 5 is a side view of the boat of FIG. 4, taken along lines 5--5thereof;

FIG. 6 is a rear end view of the portion of the boat illustrated in FIG.4;

FIG. 7 is a detail view, partly in cross-section and partly inelevation, showing an exemplary form of connection of the transom braceto the boat sole for the boat of FIGS. 4 through 6;

FIG. 8 is a side view, partly in cross-section and partly in elevation,of an exemplary connection between the brace and transom of the boat ofFIGS. 4 through 6;

FIG. 9 is a view like FIG. 8 only showing an alternative interconnectionof a brace to a transom;

FIG. 10 is a detail cross-sectional view showing a rub strake includinga boltrope, which may be utilized with the boat according to the presentinvention;

FIG. 11 is a schematic view illustrating a manner of the construction ofan exemplary fabric enclosure, for the flexible hull portion of a boataccording to the invention;

FIG. 12 is an end schematic view illustrating another manner ofconstructing an exemplary fabric enclosure for the flexible hull portionof the boat according to the invention;

FIG. 13 is a detail cross-sectional view of another embodiment of anexemplary anchor for use with the boltrope of FIG. 1;

FIG. 14 is an end view of another embodiment of an exemplary boataccording to the present invention; and

FIG. 15 is a detail end view, partly in cross-section and partly inelevation, of another use of the boltrope concept according to theinvention, for the mounting of accessory components.

DETAILED DESCRIPTION OF THE DRAWINGS

Attention is directed to U.S. Pat. No. 4,498,413 and co-pendingapplication Ser. No. 572,372 filed Jan. 20, 1984, the disclosures ofwhich are hereby incorporated by reference herein. The invention relatesto an improvement for a rigid inflatable boat of the type generallyshown in said co-pending application, wherein there is provided a rigidhull portion 11, and a flexible hull portion 12 (see FIGS. 3 through 5)of an RIB 10.

The rigid portion 11 of the boat 10 is disposed generally at and belowthe water line WL (see FIG. 6) of the boat, while the flexible portion12 is disposed generally at and above the water line WL. The rigid hullportion 11 may take any desired form, a number of configurations ofwhich are illustrated in said application Ser. No. 572,372. Oneparticularly advantageous form the rigid hull portion 11 may take isillustrated in FIGS. 2 and 3, and comprises upper and lower fiberglassshells 14, 15 filled with a solid buoyant material, such as foam, cork,or the like, 16. The shells 14, 15 also include side portions 14', 15'thereof, and foam, or plywood 17, may be disposed between the portions14', 15'. Alternatively those portions 14', 15' may mate and beultrasonically welded, glued, or otherwise attached together. In theembodiment of the boat 10 illustrated in the drawings, the sole isgenerally flat, although a wide variety of other configurations also maybe provided.

The flexible portion 12 of the hull of the boat 10 according to thepresent invention includes an enclosure or shroud 20 of flexiblematerial, which enclosure completely circumferentially surrounds aplurality of bladders 21 (see FIGS. 1, 3, and 5 in particular). Thebladders 21 may be formed of elastomeric material or the like, anddifferent constructions and varieties of bladders are more fullydescribed in said application Ser. No. 572,372.

The enclosure 20 may be formed of almost any flexible material that iscapable of performing a protecting function, and properly positioningthe bladders 20 in place during use, and in some situations the bladderand enclosure may even be made integral. While enclosure 20 may be madeof unsupported plastic, supported rubber, woven nylon, nonwoventextiles, precoated or prefinished textiles, in-situ coated or finishedtextiles, or the like, preferably the enclosure 20 is formed of aconforming fabric. Typical conforming fabrics include circular knitfabrics, flat (e.g. warp) knit fabrics, felts, needlepunched fabrics,non-woven fabrics, triaxially woven fabrics, velvet, fabrics woven withelastic, and braided textiles. It is desirable for the fabric of theenclosure 20 to have "memory" to its use position (see FIGS. 4 through 6in particular) wherein it completely circumferentially surrounds aninflated bladder. This may be accomplished by impregnating theconforming fabric with a resin, or like finishing agent, while it is inits inflated position, and curing it in that position; or by cutting andsewing a conforming fabric, or non-conforming fabric, into the desiredshape. In this regard attention is particularly directed to FIG. 11which shows a former 24 on which a length of conforming fabric 25 isdisposed, and the resin therein cured.

FIG. 11 more particularly illustrates the construction of a specificenclosure 20 material wherein a second fabric, such as a fabric 26having stretch properties, is spirally wrapped around the fabric 25. Thesecond fabric 26 is impregnated with resin, or like finishing agent, andafter construction of the final fabric is subjected to cure by a heatsource 27, or the like, to provide an integral final fabric which serveswell as the enclosure 20 after it is removed from the former 24. Duringuse, preferably the fabric constructed according to FIG. 11 is invertedso that the spirally developed second fabric 26 is disposed on theinterior of the final fabric, and the fabric 25 on the outside.

FIG. 12 illustrates the construction of another specific enclosurematerial 20 that has "memory" to a use position wherein it completelycircumferentially surrounds an inflated bladder. In this embodiment thefirst fabric 25' is disposed on a former, and then a second fabric 26'is disposed along a part of the circumference thereof, and along asubstantial part of the length thereof. The fabrics 25', 26' areattached together in any desired way. For instance the fabric 26' may beimpregnated with resin, or like finishing agent, and cured. As in theFIG. 11 embodiment, the fabric 20 in FIG. 12 may be inverted before use.

According to the present invention, particular connecting means areprovided for connecting the flexible hull portion 12 to the rigid hullportion 11. The particular connecting means according to the presentinvention comprises bead means, such as boltrope 30 (see FIGS. 1 and 3in particular) and cooperating grooved anchor means, such as the anchorportion 31 (see FIGS. 2 and 3) which is C-shaped in cross-section withthe groove 32 therein generally facing upwardly and extending generallyhorizontally. Of course other bead means and grooved anchors may beprovided, but the boltrope is particularly advantageous.

The boltrope 30 may be connected to the enclosure 20 by any suitablemeans. Preferably, as illustrated in FIG. 1, a length of textile tape34, which extends substantially the entire length of the boltrope 30, iswrapped around it, and the end portions 35, 36 thereof are stitched toend portions 37 of the enclosure 20 sandwiched therebetween, thestitching shown generally by reference numeral 38. The textile tape 34may be of any conventional material, preferably an abrasion resistantmaterial that will not degrade when exposed to sunlight, such as a wovenpolyester fabric, or nylon.

The anchor portion 31 preferably is part of an aluminum or plasticextrusion, and it may be welded or otherwise attached--as indicated at39 in FIG. 2--to a plate 40 (e.g. an aluminum plate). Alternatively aconstruction of the anchor can be devised wherein a single aluminum orplastic extrusion can be provided for the elements 39, 40.

The anchor preferably is attached to the side portions 14', 15' of therigid hull portion 11 by one or more fasteners, such as bolt 41 in FIG.2, which engages the plate 40 and, through nut 42 and washer 43 whichengages the inner shell portion 14'.

The anchor 31 is continuous around the circumference of the boat, exceptat the transom (50), and is preferably secured approximately every 12inches along the periphery of the rigid hull portion 11 thereof by abolt 41, etc. Preferably no bolt 41 is provided at the center line ofthe bow of the boat, but rather a towing eye is provided at the centerline of the bow. The anchor 31 may occasionally be discontinuous toreceive clamps, cleats, or the like, if desired.

It is desirable to affix the boltrope 30 with respect to the rigid hullportion 11 once it has been threaded through the anchor 31. Inflation ofthe bladders can effect affixation if the rigid hull portion 11 isproperly shaped (e.g. see FIG. 14). Affixation may be accomplished byany of a wide variety of other means, such as by extending portions ofthe boltrope 30 past the ends of the enclosure 20 or tape 34, andattaching those extending ends of the boltrope by any of a wide varietyof clamps or cleats, to the fixed hull portion 11. Alternatively theclamps or cleats can be provided where the anchor 31 is discontinuous,and clamping may be effected at intermediate positions along the lengthof the boltrope and anchor, as well as at the ends thereof. Anotherboltrope anchoring means, which is illustrated in FIG. 3, comprises ascrew 46 passing through anchor 31 adjacent the stern of the boat, andpassing through the boltrope at that point to thereby hold the boltrope30 stationary with respect to the rigid hull portion 11.

The boat 10 according to the present invention also preferably comprisesa transom. The transom preferably comprises a plate 50 (see FIGS. 3through 6) of relatively rigid material, such as fiberglass, wood, oraluminum, and desirably is pivotally connected to the rigid hull portion11. This may be accomplished by hinge means 51 (see FIGS. 3 and 6) whichallow pivotal movement of the transom 50 with respect to the rigid hullportion 11 about a generally horizontal axis extending in the dimensionof elongation A--A of the transom 50. The transom 50 preferably includesa central portion 52 thereof which is ideal for mounting a motor, or thelike, and includes side portions 53, 54 (see FIGS. 4 through 6) whichare scalloped to provide a contour in which the flexible hull portion 12seats. The scalloped portions 53, 54 preferably extend a substantialdistance in the dimension B which is along the side of the boat 10, andgenerally perpendicular to the plane of the transom 50.

Preferably at the hinge line between the rigid hull portion 11 and thetransom 50 a rubber gasket 55 (see FIG. 3) is provided to prevent waterfrom leaking into the boat once the transom 50 has been moved to itsin-use, generally upright position (as illustrated in FIGS. 3 through6). Also, to facilitate the contour of the transom 50 to the flexiblehull portion 11, a filler block 56 (see FIG. 3) is fixed to the transom50, as by nailing and gluing, or fixed to the rigid hull portion 11.

To hold the transom 50 in its operative upright position, brace meansare provided, such as the two spaced braces 59, 60 illustrated in FIGS.4 and 5 respectively. Each of the braces 59, 60 preferably comprises analuminum rod which has a designed length, cooperating with the fittingstherefor, so that the transom 50 is held in a substantially verticalposition during use. As illustrated most clearly in FIG. 7, one formthat the brace 59 or 60 may take is a rod having a slot 61 formed at thebottom end thereof, and another slot (not shown) formed at the topthereof. A flange 62 extends into the slot 61 and pivotal attachmentbetween the components 59, 62 is provided by a pin 63 passing throughthe slotted end of the brace 59 and the flange 62. The flange 62 may beaffixed to the sole of the rigid hull portion 11 utilizing the block 64,and a plurality of suitable fasteners 65.

As illustrated in FIG. 8, the top slotted end of the brace 59 receivesthe flange 67 therein, and a pin 68 connects the components 59, 67together in the same way that the pin 63 attaches the components 59, 62together. The flange 67 is attached to the transom by a plurality ofsuitable fastening means, such bolts 68, for instance two bolts 68provided on either side of the flange 67.

FIG. 9 illustrates an alternative way in which a brace may be mounted tothe transom (or sole). In FIG. 9, the brace 59' does not contain aslotted end, but rather it is welded, as indicated by reference numeral70, to a plate 71. The plate 71 includes an opening (not shown) thereinwhich is adapted to receive a screw 72 therein. When the screw 72 ispassed through the opening in the plate 71, with the head 73 of thescrew of 72, and a washer 74 engaging the face of the transom 50opposite the brace 59', a wing nut 75 is then screwed into operativeassociation with the screw 72, to hold the brace 59' in place.

Since there is a pivotal connection between the transom 50 and the rigidhull portion 11, by removing the braces 59, 60 the transom 50 may befolded into, or out of, the boat (depending upon the particular locationand orientation of the hinges 51), or the transom may be removed byremoval of the hinge pins, so that the boat may assume a low volumeconfiguration for ease of transport or storage.

As will be seen most clearly in FIGS. 4 and 5, the transom 50 helpsposition the flexible hull portion 12 at the aft portion thereof. Inorder to facilitate this positioning, and so that a fendering action isprovided, preferably a significant portion--i.e. portion 79 in FIGS. 4and 5--of the flexible hull portion 12 extends aft of the transom 50.Also to facilitate positioning of the flexible hull portion 12, it isloosely attached to the braces 59, 60. This may be accomplished byproviding a ring 80 (see FIGS. 4 and 5) on each of the braces 59, 60which can slide up and down on the ring, to which ring a portion offabric is attached, which in turn is sewn to the fabric providing partof the enclosure 20. A substantial amount of play (e.g. 10°) must beprovided at this attachment in order to facilitate removal of the braces59, 60.

In order to extend the life of the flexible hull portion 12 at the aftportions thereof, preferably extra layers of fabric are provided as partof the enclosure 20 at the portions thereof adjacent the transom 50.These extra layers preferably are provided both at the portion of theenclosure 20 which abuts the scalloped transom portions 53, 54, and towhich the rings 80 are attached.

If desired, intermediate positioning components can also be providedalong the sides of the boat 10 to properly position the flexible hullportion 12 with respect to the rigid hull portion 11.

According to another aspect of the present invention, a simple yeteffective rub strake may be provided, such as illustrated generally byreference numeral 83 in FIG. 4. The rub strake may extend along only aportion of the flexible hull portion 12, or along the entire sidecircumference thereof. The rub strake 83 is seen more clearly in FIG.10, and comprises a boltrope 84 which receives a grooved lug, or aplurality of adjacent lugs, 85 formed of some sort of a resilientmaterial (such as rubber or a soft plastic). FIG. 10 also illustratesanother form--besides that illustrated in FIG. 1--for attaching aboltrope to the fabric enclosure 20. As illustrated in FIG. 10, thefabric enclosure 20 is a conforming fabric, or the like, and theboltrope 84 is merely disposed in a looped portion thereof, and sewn inplace by stitching 86, a single continuous fabric portion thuscompletely surrounding the boltrope 84 and the bladders 21.

While the flexible hull portion 12 may be disposed along any desiredpercentage of the circumference of the rigid hull portion 11 (dependingupon the construction of the portion 11), in the preferred embodimentillustrated in the drawings the flexible hull portion 12 extends alongthe entire circumference of the rigid hull portion 11 except along thetransom 50.

FIGS. 13 and 14 illustrate alternative constructions of the anchor forthe boltrope associated with the flexible hull portion 12. In both FIGS.13 and 14 the anchor is formed as part of the rigid hull portion. Forinstance in FIG. 13, the part 82 of the rigid hull portion, whichincludes an interiorly formed shelf 83, has an arcuate upper portion 84.This cooperates with a complimentary arcuate cut-out 85 in the deck 86,the arcuate portions 84, 85 having the upwardly facing groove 87therebetween, and adapted to receive the boltrope of FIG. 1 therein.Preferably the hull portion 82 is made of fiberglass or aluminum, andthe deck 86 of fiberglass or a core material.

In the FIG. 14 embodiment, a continuous semi-circular depression 90 isformed at peripheral sections of the rigid hull portion 111 (except adepression 90 normally is not provided at the stern of the boat). At thebottom of the depression 90 is formed an upwardly facing C-shaped groove92, which receives the boltrope associated with the flexible hullportion 21.

The boltrope concept can also be utilized to mount accessory componentson the upper part of the flexible hull portion 12. In the FIG. 15embodiment, the boltrope 93 is held to the enclosure fabric 20 bystitching 94 or the like, and is received by a C-shaped lug 95. The lug95 has extending upwardly therefrom a suitable component adapting thestructure for its intended use. For instance the lug 95 may have a cleator oarlock component extending upwardly therefrom. Alternatively, asillustrated in FIG. 15, a mounting projection 96 for a thwart extendsupwardly from the lug 95, with the thwart 97 being attached at each endthereof to a component 96. Note that the thwart 97 in addition toperforming a seat function also provides a positioning function for theflexible hull portion 12. Of course other accessory components may alsobe provided associated with the lug 95, as desired.

In a typical construction and use of a boat 10 according to theinvention, with the bladders 21 deflated the user takes one end of theboltrope 30, threads it through the anchor 31 with the groove 32 in theanchor 31 loosely receiving the plies 35-37 therein, until the flexibleportion 12 is disposed around the entire circumference of the rigid hullportion 11 except for the transom 50. The boltrope 30 is then attachedat either end thereof in this position, as by utilizing screws 46 (seeFIG. 3), or other structures previously described.

The transom 50 is pivoted about hinges 51 so that it is in the uprightposition, the braces 59 and 60 are attached to the transom 50, as bypassing a pin 68 through an upper end of each of the braces 59, 60 and aflange 67 received thereby, so that the transom is held in this uprightposition, properly positioning the enclosure 20. Then the bladders 21are inflated by any suitable means such as shown in said co-pendingapplications. A motor may be mounted at the portion 52 of the transom 50(either before or after it is mounted in an upright position), and theboat 10 used for any desired purpose.

It will be seen that according to the present invention the utilizationof the boltrope allows modular construction of the flexible hull portion12, ready interchangeability of components, ready mounting ofaccessories, a low volume configuration for storage, and ease of removalfor repair or replacement.

It will thus be seen that according to the present invention a simple,versatile, and effective RIB has been provided. While the invention hasbeen herein shown and described in what is presently conceived to be themost practical and preferred embodiment thereof, it will be apparent tothose of ordinary skill in the art that many modifications may be madethereof within the scope of the invention, which scope is to be accordedthe broadest interpretation of the appended claims so as to encompassall equivalent structures and devices.

What is claimed is:
 1. A boat having a hull and comprising: a rigid hullportion disposed generally at, and below, the water level of the hull;aflexible hull portion, said flexible hull portion including an enclosureof flexible material, said enclosure completely circumferentiallysurrounding a plurality of inflatable bladders; said flexible hullportion being positioned generally at, and above, the water level of thehull; and connecting means for connecting said flexible hull portion tosaid rigid hull portion, said connecting means comprising a boltropeconnected to said flexible hull portion along its length, said rigidhull portion having anchor means for engaging and holding said boltropesubstantially along the entire length of said boltrope, said anchormeans comprising a substantially C-shaped channel, said channel havingand said boltrope having interconnecting restraining means to preventrelative displacement between said channel and said boltrope regardlessof the condition of said inflatable bladders, said enclosure comprisinga fabric, and further comprising a rub strake formed around at least aportion of the side of said flexible hull portion, said rub strake beingformed by a boltrope secured to said enclosure at said side of saidflexible hull portion, and a grooved lug of resilient material receivingsaid boltrope and disposed outwardly of said enclosure.
 2. Apparatus asrecited in claim 1 wherein said fabric comprises a conforming fabric,and wherein said boltrope is operatively connected to said conformingfabric by textile tape of an abrasion resistant material, the textiletape surrounding the boltrope and attached to the conforming fabric bystitching.
 3. Apparatus as recited in claim 1 wherein said fabric is atube of fabric, comprising a conforming fabric, and wherein saidconforming fabric surrounds said boltrope and is stitched adjacent thepoints where it surrounds said boltrope, so that the boltrope is held inplace.
 4. Apparatus as claimed in claim 1 wherein said interconnectingmeans comprises a pin member extending through said boltrope and saidanchor portion.
 5. Apparatus as recited in claim 1 wherein said fabriccomprises a conforming fabric formed from a first conforming fabricspirally wrapped with a second fabric, the first and second fabricsbeing operatively held together by a finishing agent.
 6. Apparatus asrecited in claim 1 wherein said fabric comprises a conforming fabric,and further comprising means for mounting accessory components extendingupwardly from said flexible hull portion, said means comprising aboltrope secured to said enclosure at the top of said flexible hullportion, and a grooved lug receiving said boltrope, said grooved lugincluding a projection extending upwardly from said flexible hullportion.
 7. Apparatus as recited in claim 1 wherein said fabriccomprises a conforming fabric selected from the group consistingessentially of circular knit fabrics, conforming fabrics with a secondfabric adhered thereto to impart memory, braided fabrics, flat knitfabrics, velvet, triaxially woven fabrics, felts, needlepunched fabrics,non-woven fabrics, woven fabrics containing elastic, and combinationsthereof.
 8. Apparatus as recited in claim 1 wherein said fabric isselected from the group consisting essentially of circular knit fabrics,first and second fabrics adhered together, braided fabrics, flat knitfabrics, velvet, triaxially woven fabrics, felts, needlepunched fabrics,non-woven fabrics, woven fabrics containing elastic, and combinationsthereof.
 9. Apparatus as recited in claim 1 wherein said boltrope isoperatively connected to said enclosure by textile tape of an abrasionresistant material, the textile tape surrounding the boltrope andattached to the flexible material of the enclosure by stitching. 10.Apparatus as recited in claim 1 wherein said fabric is a tube of fabric,and wherein said fabric surrounds said boltrope and is stitched adjacentthe points where it surrounds said boltrope, so that the boltrope isheld in place.
 11. Apparatus as recited in claim 1 wherein said fabricis capable of conforming to the shape of the inflated bladders, saidfabric having been impregnated by a finishing material when in aconfiguration comparable to its configuration when surrounding saidinflated bladders so that the conforming enclosure fabric will tend toretain its configuration conforming to the inflated bladders.
 12. A boathaving a hull, and comprising:a rigid hull portion disposed generallyat, and below, the water level of the hull; a flexible hull portion,said flexible hull portion including an enclosure of flexible material,said enclosure completely circumferentially surrounding a plurality ofinflatable bladders; said flexible hull portion being positionedgenerally at, and above, the water level of the hull; connecting meansfor connecting said flexible hull portion to said rigid hull portionincluding a C-shaped clamp fixed to said rigid hull portion and aboltrope flexibly connected to said hull portion with means fixedlyinterconnecting said clamp and said boltrope to prevent relative slidingmovement between said clamp and said boltrope; a transom removablyconnected to said rigid hull portion for movement relative to said rigidhull portion; transom brace means operatively connected to said transomand said rigid hull portion for holding said transom in a generallyupright position and preventing movement thereof relative to said rigidhull portion; and said brace means being loosely secured to saidenclosure material to facilitate proper positioning of said enclosure.